Unusual patterns of neural tube defects in a high risk region of northern China.

OBJECTIVE: To study the prevalence of different types of neural tube defects (NTDs) in Luliang Prefecture, Shanxi province, where the prevalence of NTDs is unusually high and the correlation between NTDs prevalence and patterns. METHODS: A surveillance population-based birth defects was performed in Luliang Prefecture, Shanxi province. RESULTS: The results of our study showed that the prevalence of NTDs was 2-fold higher in Luliang Prefecture than in other areas of Shanxi province. Unusual patterns of NTDs were found, however, multiple NTDs were relatively common in Luliang Prefecture, accounting for over 13% of all NTDs cases in China. CONCLUSION: The prevalence of NTDs is associated with its patterns.

Maternal serum vitamin B12, folate and homocysteine and the risk of neural tube defects in the offspring in a high-risk area of China.

OBJECTIVE: To examine the association between the risk of neural tube defects (NTD) and maternal serum vitamin B12, folate and homocysteine in a high-risk area of China. DESIGN: A case-control study was carried out in Luliang mountain area of Shanxi Province. SUBJECTS/SETTING: A total of eighty-four NTD pregnancies and 110 matched controls were included in the study; their serum vitamin B12 and folate concentrations were measured by chemiluminescent immunoenzyme assay and total homocysteine concentrations by fluorescent polarisation immunoassay. RESULTS: Serum vitamin B12 and folate concentrations were lower in NTD-affected pregnant women than in controls (P < 0.01). Serum total homocysteine was higher in the NTD group than in controls at less than 21 weeks of gestation (P < 0.01). Adjusted odds ratios revealed that women with lower vitamin B12 (adjusted OR=4.96; 95 % CI 1.94, 12.67) and folate (adjusted OR=3.23; 95 % CI 1.33, 7.85) concentrations had a higher risk of NTD compared to controls. Based on dietary analysis, less consumption of meat, egg or milk, fresh vegetables and fruit intake would increase the risk of NTD. CONCLUSIONS: Lower serum concentrations of folate and vitamin B12 are related to the increased risk of NTD in high-risk populations. Both folate and vitamin B12 intake insufficiency could contribute to the increased risk of NTD. A dietary supplement, combining folate and vitamin B12, might be an effective measure to decrease the NTD incidence in these areas.

[Occurrence of structural birth defect in high-prevalent areas of China].

OBJECTIVE: This research was to compare the occurrence levels of birth defect, to describe the distribution of primary birth defects in different range of monitored ages and to provide data to China birth-defect monitoring system. METHODS: A retrospective study on birth defect was conducted in two counties, Shanxi province, China, which covered birth defects among fetuses after 20 weeks' gestational age from 2002 through 2004. Data collected on birth defect cases mainly included extrinsic and visceral anomaly. RESULTS: The occurrence rates of the monitored structural birth defects significantly increased with the increase of age. The occurrence rates were 17.6, 34.0, 43.6, and 53.7 per 1000 births, for different statistical range, from 20-week to 27-week gestational age, 7 days, 1 year and 3 years after birth, respectively. The range from 28-week gestational age to 7 days after birth was usually regarded as the routinely monitored range. If the occurrence rate was calculated from the 20-week gestational age, it appeared a 2.1-time increase. However, if the range was changed to 1 or 3 years after birth, the occurrence rate increased to 2.7 or 3.3 times high, respectively. The distribution of time when birth-defect was identified was significantly different by categories with majority of neural tube defect cases diagnosed at antepartum or 7 days after birth. Visceral defects were mainly found at 7 days after birth but increased with age, even some were diagnosed at 1 year after birth. CONCLUSION: The routine Chinese monitoring program might detect approximately 1/3 of those structural birth defects with the base of current technique and monitoring range from 28-week gestational age to 7 days after birth. The result of our findings should be of help to other related studies.

Correlation between birth defects and dietary nutrition status in a high incidence area of China.

OBJECTIVE: To investigate the association between birth defects and dietary nutrient intake in a high risk area of China. METHODS: A dietary survey was performed and serum folic acid was measured in women whose pregnancy was affected by neural tube defects (NTDs) or unaffected by any birth defects (BDs) in Zhongyang and Jiaokou Counties in Shanxi Province of China. RESULTS: The local average consumption of foods including dark green vegetables, fruits, fat and meat, and nutrient intake (e.g., energy, protein, retinol, riboflavin, vitamin E, and selenium) were lower than the national average level. In women of childbearing age, these regions, the intake of nutrients was much lower than the recommended nutrient intake (9%-77%). The case-control dietary nutrition study of women whose pregnancy was affected by BDs (including NTDs and congenital heart defects) demonstrated that, in early pregnancy, adequate nutrition (i.e., eating meat, fresh vegetables, fruit more than once a week) was a protective factor, while eating germinated potatoes was a risk factor. The geometrical mean (p5-p95) of serum folic acid in women with NTD birth defects was 9.6 nmol/L (3.6, 23.03), which was significantly lower than that in normal women (14.03 nmol/L). CONCLUSION: Women of childbearing age in the two counties of Shanxi Province, China, have a marked insufficient intake of some nutrients, especially folic acid, zinc, vitamins A and B12. This nutrient deficiency may be an important risk factor for the high prevalence of birth defects in these regions. Therefore, adequate dietary nutrition in early pregnancy can prevent BDs.

Vitamin A deficiency and child feeding in Beijing and Guizhou, China.

BACKGROUND: Vitamin A deficiency (VAD) is one of the three major micronutrient deficiencies in the world. In order to investigate the status of VAD and child feeding in China, we conducted the survey in Beijing city and Guizhou province. METHODS: We included a high socioeconomic area (Beijing) and a low socioeconomic area (Guizhou province) in China in our study. Participants included 1236 randomly selected children aged 0-71 months from stratified clusters (628 in Beijing and 608 in Guizhou), 409 from urban and 827 from rural areas. A food intake frequency questionnaire was used for dietary assessment. Fluorescence microanalysis was carried out to measure serum retinol concentrations. Serum retinol cut-off values of less than 20 microg/dl and 30 microg/dl were defined as sub-clinical VAD and suspected sub-clinical VAD, respectively. RESULTS: No xerophthalmia or night blindness was found. The mean concentration of serum retinol was 31.5 microg/dl in the high socioeconomic group, and 26.5 microg/dl in the low socioeconomic group. Rural infants had lower concentrations of serum retinol compared with the urban ones (26.9+/-8.1 microg/dl vs 31.8+/-7.3 microg/dl). The prevalence of sub-clinical VAD among all the children was 7.8%, and increased to 15.7% in children from the low socioeconomic group. In infants from the high socioeconomic area, the prevalence of suspected subclinical VAD was 38.0%, increasing to 59.5% in infants from the low socioeconomic area. The children from the low socioeconomic area had significantly lower fequency of intake of meat than the children in other groups. The prevalence of suspected sub-clinical VAD was higher in the children with lower consumption frequency of vitamin A rich foods than the children with higher consumption frequency of vitamin A rich foods. CONCLUSIONS: VAD appears to be a moderate public health problem in certain areas of China. In areas with low socioeconomic status, VAD in childrean is more severe, and infants may be the group at the highest risk for VAD. Inadequate intake of vitamin A rich foods may result in VAD. A comprehensive long-term national strategy needs to be fostered in China for the treatment and prevention of the deficiency.

High prevalence of NTDs in Shanxi Province: a combined epidemiological approach.

BACKGROUND: Shanxi Province has historically reported a high prevalence of NTDs. In order to establish baseline rates for NTDs and discuss the risk factors associated with sociodemographic, maternal characteristics, and geographic factors, we performed the present study using an approach combining population and hospital-based methodologies. METHODS: We used chi(2) and Fisher's exact tests to evaluate variation in the prevalence by selected covariates and computed crude ORs and 95% CIs. Adjusted odds ratios (AORs) were performed using logistic regression with all the covariates included in the model. RESULTS: The overall NTD prevalence during the 3 year study period was 199.38 per 10,000 births, with a higher NTD prevalence clustered in 46 villages within this geographic area. However, no statistical significance was found between NTD prevalence and the elevation of the villages or their distance from coal plants. AORs revealed women aged 20 and above had a lower risk of NTDs compared to those younger than 20 (AOR range 0.4-0.5). A higher risk of NTDs was observed among female infants (AOR 1.50; 95% CI: 1.04-2.17), women with four or more previous births (AOR 2.80; 95% CI: 1.20-6.52), and a previous history of birth defects (AOR 3.23; 95% CI: 1.46-7.12). CONCLUSIONS: This study has documented a high prevalence of NTDs in Shanxi. Similar variations to other reports were found in the risk of NTDs by maternal demographic characteristics and a clustering of NTDs in certain villages that require further exploration.

Vitamin A status among children in China.

OBJECTIVE: The objective of this study was to assess the prevalence of vitamin A deficiency (VAD) in children under 6 years old in China and to identify risk groups for VAD. DESIGN: A cross-sectional survey was conducted in 14 provinces from coastal, inland and western geographic areas in China. SETTING: One city (urban) and two counties (rural) were randomly selected from each province as survey areas. SUBJECTS: About 200 children aged 0-6 years were randomly selected in each survey area. A blood sample was collected from each child. Data on sociodemographics and nutrition were obtained by interview of the mother or principal caregiver. Fluorescence microanalysis was used to analyse serum retinol concentration. RESULTS: VAD (serum retinol <0.7 micro mol l(-1)) was observed in 957 out of 7,826 children aged 0-6 years (12.2% of the entire study population), whereas severe VAD (serum retinol <0.35 micro mol l(-1)) was found in 39 children (0.5%). The highest prevalences of VAD at >1 year of age were observed among children of mothers with minority ethnicity (22.7%) or poor education (19.8%) and in the poor western area (17.4%). CONCLUSIONS: VAD is a nutritional problem in children in China. Children living in the poor western area, having a mother with minority ethnicity or a mother with poor education have a high risk of VAD.

[Prevalence of vitamin A deficiency in children under six years of age in Tibet, China].

OBJECTIVE: To understand the prevalence of vitamin A deficiency (VAD) among children under six years of age in Tibet, China. METHODS: Totally, 1 257 children under six years of age were selected from two cities, two farming counties, two semi-farming counties and two livestock farming counties with stratified cluster sampling to asses VAD status in Tibet. Family information, children's feeding and disease history in the previous two weeks were collected by questionnaire. Blood specimen was collected from each child and serum was separated for detection of vitamin A concentration with microfluorescent spectrophotometry. RESULTS: Totally, 1 257 children under six years of age were surveyed, with 635 boys, 622 girls, 862 aged over two years, and 98.5% of Tibet nationality. Six cases of night blindness and two cases of xerophthalmia were detected from them, with prevalence of clinical VAD of 0.96%. Eighteen of 1071 mothers with children under six years of age were found suffering from night blindness, accounting for 1.7%. Clinical cases of VAD both in children and mothers came from all four sampling strata. Average serum concentration of vitamin A and prevalence of subclinical VAD (serum vitamin A lower than or equal to 0.70 micromol/L) was 1.15 micromol/L and 5.4% and 1.12 micromol/L and 4.7% in cities and livestock farming counties, respectively, significantly higher than those in farming (1.04 micromol/L and 11.0%) and semi-farming counties (1.05 micromol/L and 12.3%), respectively, as compared to average levels of 1.09 micromol/L and 8.4% in the autonomous region as a whole. Prevalence of subclinical VAD in children under six months and those aged six to eleven months were 22.2% and 13.3%, respectively, significantly higher than those in children aged one year (8.5%), two to three years (5.4%) and four to five years (7.9%), respectively. There was also significant difference in serum level of vitamin A between children at varied ages, but no significant difference both in serum level of vitamin A and prevalence of subclinical VAD between gender was found. CONCLUSIONS: In general, status of VAD in children of Tibet was milder than that at national level. But, moderate subclinical VAD in some areas, such as farming and semi-farming counties, did exist, so vitamin A supplementation aiming to children, especially those under one year of age, in those areas should be urged.

A national sampling survey on birth weight in 1998 in China: mean value and standard deviation.

OBJECTIVE: To understand the distribution of live birth weight in China. METHODS: A national survey on live birth weight was performed during July-October, 1998 in China, with stratified sampling. Totally, 22 350 live newborns (11 584 males and 10 766 females) with 28 weeks or more of gestation were measured for their birth weight in the sampling sites during 1998. RESULTS: The ratio of male to female newborns measured was 1.08. The rates of multiple birth and preterm birth (< 37 weeks of gestation) were 1.8% and 3.5%, respectively. Live birth weight was higher in the urban areas (3 301 g) than that in the rural area (3 225 g) (t = 9.4. P < 0.001), the highest in the coastal areas (3 262 g), middle in the inland areas (3 254 g) and the lowest in the remote areas (3 115 g) (F = 177.9, P < 0.001), with a decreasing trend. Live birth weight in the first-class rural areas approximated to that in the urban areas, and that in the second-class, third-class and fourth-class rural areas decreased significantly. The average live birth weight in the fourth-class rural areas was 200 g lower than that in the urban areas. CONCLUSIONS: Generally, the average live birth weight in China was closed to that in the developed countries. But, a big difference in the average live birth weight between regions with varied economic development and health care condition was observed. An intervention measure should be implemented in the poverty-stricken rural areas to increase their average live birth weight.

Sampling survey on low-birth weight in China in 1998.

OBJECTIVE: To study the weight of live births and incidence of low-birth weight (LBW) in China. METHODS: A national survey on the weight of live births with gestational ages of 28 weeks or over in 16 cities and 28 counties of 11 provinces in China was carried with stratified sampling during July to October, 1998. RESULTS: Totally 22 350 live newborns, 11 584 males and 10 766 females, with gestational ages of 28 weeks or more in sampling sites were measured at their birth. Rates of multiple births and preterm birth (< 37 weeks of gestation) were 1.8% and 3.5%, respectively. LBW rates were 4.20% and 6.26% for urban and rural areas, respectively, with a national weighted-average of 5.87%. Full term births (>/= 37 weeks of gestation) accounted for 61.2% and 71.6% of the babies with LBW in national and rural areas, respectively. Their average birth weight was 3 301 g and 3 225 g in urban and rural areas, respectively, with statistically significant difference, and 3 280 g and 3 173 g for boys and girls, respectively, approaching to the values recommended by the World Health Organization (WHO). Live birth weight in the coastal, inland, and remote areas appeared a trend of gradual decrease. Early neonatal mortality of babies with LBW was 50.0 per thousand and 179.4 per thousand in urban and rural areas, respectively, with a national average of 151.5 per thousand, significant higher than those with normal birth weight. CONCLUSIONS: The average birth weight and LBW rate in live births of China were close to those in the developed countries, and there was significant difference in them between varied regions. The majority of LBW in China was attributed to intrauterine growth retardation (IUGR). Early neonatal mortality in babies with LBW was significantly higher than that with normal birth weight. Further intervention measures should be implemented.

A case-control study on risk factors for low birth weight in China.

OBJECTIVE: To identify the risk factors for low birth weight (LBW) in Chinese newborns with varied characteristics. METHODS: A 1:1 matched case-control study, with 999 babies of LBW was performed in 44 counties of 11 provinces in China during July to October, 1998 for identifying their risk factors using simple and multivariate logistic regression models. RESULTS: The determinants of LBW in China included factors, such as multiparity (OR = 106.9), preterm birth (OR = 18.7), abnormal maternal health status (OR = 2.61) and maternal malnutrition (OR = 3.42), maternal medical conditions during pregnancy (OR = 1.93), maternal schooling (OR = 1.43), et al. Distribution of the risk factors for LBW was significantly different between coastal, inland and remote areas. LBW was mainly attributed to intrauterine growth retardation (IUGR) (71.6%) in the rural areas, and to multiparity and preterm birth, in addition to IUGR, in the urban areas. There was different in the risk factors for LBW with preterm births and IUGR. CONCLUSIONS: It is an effective way to reduce incidence of low birth weight in China that all measures for prevention and control should be relevant to its risk factors.

Prevalence of subclinical vitamin A deficiency and its affecting factors in 8 669 children of China.

OBJECTIVE: The survey will reveal current status of subclinical vitamin A deficiency (SVAD) and explore its affecting factors in children of China. METHODS: Totally 8 669 children aged under 6 years were randomly selected from 14 provinces for clinical examination, health and dietary questionnaire and serum level of vitamin A measurement with fluorescence method. The cut-off value for SVAD was defined as

[Survey on vitamin A deficiency in children under-6-years in China].

OBJECTIVE: To understand the prevalence and spatial distribution of vitamin A deficiency (VAD) in China among children at ages under six years. METHODS: About 8,600 children under 6 years of age in 14 cities and 28 counties of 14 provinces were selected with stratified cluster sampling for survey, including interview with questionnaire for their family information and nutritional status. Blood specimens were collected for measuring serum level of VA with fluorescent spectrophotometry in laboratory. RESULTS: Totally, 8,669 children under 6 (2,877 in urban area and 5,792 in rural area) were surveyed in 14 provinces, with 4,629 males and 4,040 females. Eight cases of night blindness and seven cases of xerophthalmia were found among the children at ages of two to five years. Sixty-one mothers of the children in this group were also found suffering from night blindness. All the cases of night blindness and xerophthalmia both in children and mothers were living in rural areas. Based on their serum levels of VA, 11.7% of the all 1 018 children were diagnosed as VAD, with serum VA concentrations below or equal to 0.70 micro mol/L. Prevalence of VAD was 15.0% and 5.8% in rural (23.3% in the poverty-stricken counties) and urban areas, respectively, and 5.8%, 11.5% and 16.8% in the coastal, inland and remote areas, respectively. The average serum level of VA was 1.20 micro mol/L and 0.99 micro mol/L for urban and rural areas, respectively, with a national average of 1.06 micro mol/L. And, babies under six months of age with an average serum levels of VA < or = 0.70 micro mol/L accounted for 33.4%, and those at ages of four to five years with the same level of VA accounted for 8%. There was significant difference in serum levels of VA between ages, but no significant difference between genders. CONCLUSION: VAD did exist in children of China, especially in the remote and poverty-stricken rural areas and VA supplementation is urgently needed for the children in these regions.

[The recent study and key technologies of an aided endoscopic surgical robot system].

This paper introduces the recent study and development of an aided endoscopic surgical robot system, and discusses its future trends--teleoperative robot system and telesurgery system. In addition, their key technologies are analyzed here in the paper.

[A novel miniature robotic endoscope design for intestinal inspection].

This paper makes a comparison between the traditional endoscope system and the active robotic endoscope system, discusses the human intestine-working conditions of the robotic endoscope system in detail and its design requirements. An active robotic endoscope system based on earthworn-locomotion principles is proposed here and besides, its structure and locomotion mechanism are analyzed. A new method of human intestinal intervention is brought out and it can prevent the robotic endoscope guided by a cone-shaped guide pipe from being jammed or damaged.